Hectograph duplication



Nov. 8, 1966 M. SHARKEY 3,283,709

HECTOGRAPH DUPLI CATION Filed Aug. 27, 1965 I I NVENTOR. MZVc/T /idrksy United States Patent 3,283,709 HECTQGRAPH DUPLICATION Melvin Sharlrey, 1614- Hereford Road, Hewlett, N.Y. Filed Aug. 27, 1965, Ser. No. 483,173 5 Claims. (Cl. NIL-149.5)

The present invention relates to a novel hectograph duplicating process for the imaging of dry copy sheets.

In the conventional spirit hectograph duplicating proc ess, dye images are typed or drawn onto a master sheet and these images are duplicated onto copy sheets which have been wetted with volatile dye solvent such as ethanol, the solvent dissolving dye from the images onto the copy sheet prior to its evaporation.

While the spirit process enjoys widespread commercial success, it has at least one great disadvantage which prohibits its use for certain applications such as for the production of copies of patterns used in the garment industry. The spirits used in the spirit duplicating process are very volatile and combustible and therefore present a fire and explosion hazard which prevent their open use in areas where prohibited by fire laws.

A number of dry hectograph processes have been proposed in an effort to eliminate the necessity of using volatile spirits. Most of these methods employ nonvolatile dye-solvent coatings on the copy sheets so that when master images are pressed thereagainst, portions of the master images are transferred to the copy sheet coating and gradually dissolved therein. Such a process, such as taught by US. Patent No. 3,034,428, has the disadvantages that dissolution and development of the dye color on the copy sheet is slow and uncontrollable since a mass of dye is pressure-transferred to the copy sheet and the copy sheet coating continues to dissolve the dye into areas adjacent to the areas which actually support the dye images so that broadening and blurring of the images results.

However, equally objectionable is the fact that the specially-coated copy sheets are expensive and this expense, when added to the expense of providing conventional master paper which is also costly, makes the process prohibitive for a large scale web-copy operation as is used in the pattern-copying field. I

A dry copy process has been proposed in US. Patent No 2,501,495 which employs conventional copy paper. According to this process, dye images are typed upon the resinous coating on a master sheet and the images are then pressed against a copy sheet while the master is cooled and the copy sheet is heated. This process is rather tedious due to the necessity of closely controlling the temperature of a cooling roll and a heating roll in close proximity, but more importantly this process is not a dye-dissolving process but depends upon the mass transfer of portions of the master images to each copy sheet. The images formed on the master sheet consist of solid deposits of undissolved dyestuff. Undissolved dyestuif is so easily smudged and has such a tremendous staining power that the copies imaged by this process cannot be handled without blurring the images and staining the hands and clothing. This makes such copies useless in the pattern field where staining of the fabric being cut cannot be tolerated.

With these problems and disadvantages of the prior art in mind, it is an object of the present invention to provide a novel dry hectograph copying process in which dye images are transferred to conventional dry copy papers and are later developed by means of volatile organic solvent to form intensely-colored images which are smudgeresistant and clean to the touch.

It is another object of this invention to provide a method by which hectograph copies or, more correctly, latent hectograph copies can be produced in the absence of any 3,283,709 Patented Nov. 8, 19("56 Such latent copies may be stored for long periods of time and then developed to form intensely-colored copies when desired.

These and other objects and advantages are accomplished according to this invention in a manner which will be clear to those skilled in the art in the light of the present disclosure including the drawings, in which:

FIGURE 1 is a sectional view of an arrangement for carrying out the first step or transfer step of the present process in connection with continuous master sheets and continuous copy sheets as used in the pattern-making field of the garment industry.

FIG. 2 is a sectional view of an arrangement for carrying out the second step or development step in connection with the copy sheet imaged according to FIG. 1.

The present invention is based upon the discovery that a sufiicient amount of undissolved hectograph dyestuif composition may be transferred to a succession of hectograph copy sheets in the absence of dye solvent and under the effects of pressure and, if desired, heat to form latent images on the copy sheets which may be developed by dissolution at any subsequent time to form hectograph copies of excellent quality.

This result is quite unexpected since in the past it was considered to be necessary that the hectograph copy sheet contain solvent to dissolve dyestulf from the master images, or that a sufficient amount of heat be used to melt the hectograph images over to the copy sheet. Neither of these conditions are present in the process of this invention since the present process involves a dry transfer and requires no heat. Heat may be used but the temperature is never sufficiently high to melt the hectograph composition to its flow point.

Referring to the drawing, FIG. 1 pertains to continuous web copying whereby a continuous master sheet 10 carrying undissolved dye images 11 is unwound from supply roll 20 and a continuous copy sheet 12 is unwound from supply roll 22 and the sheets are urged into pressure contact between roller 25 and pressure roller 24 to effect the transfer step after which the master sheet is wound on takeup roll 21 and the latent imaged copy sheet carrying undissolved dye images 13 is wound on takeup roll 23. If desired the master sheet may be heated prior to contact with the copy sheet such as by infrared radiation lamps 26 as illustrated and/ or by internal heating means in roller 25. Such heating is helpful to insure sufficient transfer in cases where the hectograph composition is based upon exceptionally hard waxes.

FIG. 2 illustrates an arrangement for developing the latent or undissolved dyestufi. images, formed on the copy sheet as illustrated in FIG. 1, to form intensely-colored images. Thus the copy sheet 12 carrying undissolved or undeveloped dyestuif images 13 is unwound from roll 23 and passed through a vapor chamber 27 which contains solvent vapor having a dissolving power for the undissolved dyestuif of images 13. As the copy sheet leaves the vapor chamber the images 14 thereon contain the dyestuff in dissolved condition and have a brighter, more intense color than the latent images 13 and are resistant to smudging or staining on contact.

The structure of the vapor chamber is not important nor is it necessary that the development of the latent images be caused by means of solvent vapor. For instance excellent results may be obtained by contacting the rear side of the copy sheet with a sponge or other absorbent material impregnated with liquid dye solvent. The solvent penetrates the copy sheet foundation and dissolves the dyestuff of images 13 thereon to form developed images 14.

When using continuous copy sheets of the type i1lustrated, which generally will have a width of from 30 to 60 inches, it is preferred to use solvent vapor to cause development and to use a vapor chamber such as illustrated by FIG. 2. The vapor chamber is preferably a receptacle which is completely enclosed except for oppositely-disposed openings on two sides thereof to permit entry and exit of the copy sheet. The vapor chamber contains a volatile organic solvent for the dyestufi, such as methanol, ethanol, Cellosolve or other conventional dye solvents and mixtures thereof with water, and has associated therewith heating means to vaporize the solvent or solvents.

It is a critical feature of the present invention that the hectograph dyestulf images 13 on the master sheet must be transferable at the pressure and temperature used to effect the first step of the present duplicating process so that the images formed on the copy sheets contain undissolved dyestuff capable of being dissolved when desired 1 to form intensely-colored images.

Any conventional hectograph transfer sheet may be used to image the present master sheets provided that it is based upon a wax binder material. Most wax-base hectograph compositions melt below about 120 C. and are well suited for use according to the present invention. The lower melting wax-base compositions are preferred, in that they are based upon the softer waxes which transfer readily under the efiects of pressure. The higher melting point compositions are based upon the harder waxes and function better in the present process if an amount of heat is applied thereto to soften them somewhat below their melting point to render them more pressure-transferable.

The amount of pressure used to effect transfer of portions of the master images to each copy sheet varies depending upon the hardness of the hectograph composition which in turn depends upon the ambient or applied temperature. In general it is suificient if the sheets are merely pressed into intimate surface contact between two contacting rollers. In this situation greater or lesser pressures may be obtained, as desired, by varying the thickness of the master sheet, copy sheet and/or hectograph images 11.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. The process of duplicating master images onto copy sheets which comprises the steps of (a) applying to a master sheet frangible images 'based upon a wax binder material and containing undissolved hectograph dyestutf;

(b) superposing the imaged master sheet with its images in surface contact with a succession of dry copy sheets;

(0) applying sufficient pressure to the master sheet and each copy sheet to transfer a portion of the frangible images to each copy sheet;

((1) separating each image copy sheet from the master sheet; and

(e) treating each imaged copy sheet with a volatile organic solvent for the undissolved hectograph dyestutf to dissolve the same and form intensely-colored smudge-resistant images thereon.

2. The process according to claim 1 in which step (e) is conducted by subjecting each imaged copy sheet to an atmosphere of the vapors of the said volatile organic solvent.

3. The process according to claim 1 in which step (e) is conducted by applying the said volatile organic solvent in liquid form to the surface of the copy sheet opposite to that carrying the images.

4. The process according to claim 1 in which heat is applied to the imaged master sheet to soften the images thereon prior to or during step (c).

5. The process according to claim I in which the master sheet and the copy sheets are in the form of continuous webs.

References Cited by the Examiner UNITED STATES PATENTS 2,164,685 7/1939 Kinyon 101 149.40x 2,776,907 1/1957 Carlson.

FOREIGN PATENTS 1,003,707 9/1965 Great Britain.

ROBERT E. PULFREY, Primary Examiner.

J. A. BELL, Assistant Examiner. 

1. THE PROCESS OF DUPLICATING MASTER IMAGES ONTO COPY SHEETS WHICH COMPRISES THE STEPS OF (A) APPLYING TO A MASTER SHEET FRANGIBLE IMAGES BASED UPON A WAX BINDER MATERIAL AND CONTAINING UNDISSOLVED HECTOGRAPH DYESTUFF; (B) SUPERPOSING THE IMAGED MASTER SHEET WITH ITS IMAGES IN SURFACE CONTACT WITH A SUCCESSION OF DRY COPY SHEETS; (C) APPLYING SUFFICIENT PRESSURE TO THE MASTER SHEET AND EACH COPY SHEET TO TRANSFER A PORTION OF THE FRANGIBLE IMAGES TO EACH COPY SHEET; (D) SEPARATING EACH IMAGE COPY SHEET FROM THE MASTER SHEET; AND (E) TREATING EACH IMAGED COPY SHEET WITH A VOLATILE ORGANIC SOLVENT FOR THE UNDISSOLVED HECTOGRAPH DYESTUFF TO DISSOLVE THE SAME AND FORM INTENSELY-COLOURED SMUGDE-RESISTANT IMAGES THEREON. 